I think Hyper-V will be a good base for you. Like VMWare it also has the option to create virtual networks etc. The amount of RAM you need depends on what Operating Systems you are going to use in Hyper-V. If you are going to use some Windows XP clients, it is possible to assign them 512MB ram or even less like 384MB or 256MB so you have more then enough memory.
Just be sure your motherboard supports Hardware Assisted Virtualization and the No eXecute (NX) bit, but I expect you to have a modern pc so it will work.
Hope this gives you enough information to make your decision!
Greetings, Arris
